[PATCH 3.2 52/77] ipmi: move timer init to before irq is setup

Ben Hutchings
2015-12-24T15:44:11Z

From: Jan Stancek <jstancek@redhat.com>

commit 27f972d3e00b50639deb4cc1392afaeb08d3cecc upstream.

We encountered a panic on boot in ipmi_si on a dell per320 due to an
uninitialized timer as follows.

static int smi_start_processing(void *send_info,
ipmi_smi_t intf)
{
/* Try to claim any interrupts. */
if (new_smi->irq_setup)
new_smi->irq_setup(new_smi);

--> IRQ arrives here and irq handler tries to modify uninitialized timer

which triggers BUG_ON(!timer->function) in __mod_timer().

Call Trace:
<IRQ>
[<ffffffffa0532617>] start_new_msg+0x47/0x80 [ipmi_si]
[<ffffffffa053269e>] start_check_enables+0x4e/0x60 [ipmi_si]
[<ffffffffa0532bd8>] smi_event_handler+0x1e8/0x640 [ipmi_si]
[<ffffffff810f5584>] ? __rcu_process_callbacks+0x54/0x350
[<ffffffffa053327c>] si_irq_handler+0x3c/0x60 [ipmi_si]
[<ffffffff810efaf0>] handle_IRQ_event+0x60/0x170
[<ffffffff810f245e>] handle_edge_irq+0xde/0x180
[<ffffffff8100fc59>] handle_irq+0x49/0xa0
[<ffffffff8154643c>] do_IRQ+0x6c/0xf0
[<ffffffff8100ba53>] ret_from_intr+0x0/0x11

/* Set up the timer that drives the interface. */
setup_timer(&new_smi->si_timer, smi_timeout, (long)new_smi);

The following patch fixes the problem.

To: Openipmi-developer@lists.sourceforge.net
To: Corey Minyard <minyard@acm.org>
CC: linux-kernel@vger.kernel.org

Signed-off-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Tony Camuso <tcamuso@redhat.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/char/ipmi/ipmi_si_intf.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -1148,15 +1148,15 @@ static int smi_start_processing(void

new_smi->intf = intf;

- /* Try to claim any interrupts. */
- if (new_smi->irq_setup)
- new_smi->irq_setup(new_smi);
-
/* Set up the timer that drives the interface. */
setup_timer(&new_smi->si_timer, smi_timeout, (long)new_smi);
new_smi->last_timeout_jiffies = jiffies;
mod_timer(&new_smi->si_timer, jiffies + SI_TIMEOUT_JIFFIES);

+ /* Try to claim any interrupts. */
+ if (new_smi->irq_setup)
+ new_smi->irq_setup(new_smi);
+
/*
* Check if the user forcefully enabled the daemon.
*/